diff --git a/src/CompletionProvider.php b/src/CompletionProvider.php
index 4d982d9..735990c 100644
--- a/src/CompletionProvider.php
+++ b/src/CompletionProvider.php
@@ -341,7 +341,7 @@ class CompletionProvider
             foreach ($list->items as $item) {
                 // Remove ()
                 if (is_string($item->insertText) && substr($item->insertText, strlen($item->insertText) - 2) === '()') {
-                    $item->insertText = substr($item->insertText, 0, strlen($item->insertText) - 2);
+                    $item->insertText = substr($item->insertText, 0, -2);
                 }
             }
 
diff --git a/src/Index/Index.php b/src/Index/Index.php
index 2459bbb..0c8e3e9 100644
--- a/src/Index/Index.php
+++ b/src/Index/Index.php
@@ -280,7 +280,7 @@ class Index implements ReadableIndex, \Serializable
     public function serialize()
     {
         return serialize([
-            'definitions' => iterator_to_array($this->getDefinitions(), true),
+            'definitions' => iterator_to_array($this->getDefinitions()),
             'references' => $this->references,
             'complete' => $this->complete,
             'staticComplete' => $this->staticComplete